Grey's Anatomy has had some pretty sensational storylines -- bomb explosions, plane crashes, mass shootings, etc. -- but not all of the drama happens onscreen.

Four years ago, series star Katherine Heigl caused a bit of a stir on set when she withdrew her name from Emmy consideration because she felt she hadn't been "given the material to warrant a nomination." Writers on the show were reportedly miffed, and though Heigl remained on the show for two years after the incident, her relationship with series creator Shonda Rhimes always seemed strained.

Rhimes -- who also created the Grey's spinoff Private Practice and the political drama Scandal, starring Kerry Washington -- recently sat down with Oprah Winfrey for an Oprah's Next Chapter interview airing Sunday, Dec. 9, on OWN. Among the topics they covered? Heigl's infamous Emmy snub.

"On some level it stung, and on some level I was not surprised," the Grey's head writer, 42, tells Oprah in a teaser for the interview. "When people show you who they are, believe them. I carry that with me a lot. It has served me well."

Heigl, 34, left the medical drama in 2010 to pursue film projects and spend more time with her family -- she and husband Josh Kelley adopted daughters Naleigh and Adalaide in fall 2009 and spring 2012, respectively -- but earlier this year, she expressed interest in returning to Seattle Grace Mercy West Hospital to close out her character's arc.

"I've told them I want to," the Knocked Up actress told E! News in January. "I really, really, really want to see where [Izzie Stevens] is. I just want to know what happened to her and where she went and what she's doing now. My idea is that she actually, like, figures it out, and finds some success and does really well in a different hospital."

Rhimes had other ideas, and none of them involved Izzie -- or Heigl. "I think it was really nice to hear her appreciating the show. At the same time we are on a track we have been planning," she told TV Guide in response to the star's wish to reprise her role. "The idea of changing that track is not something we are interested in right now."

Rhimes says she's grown a lot since that experience and, in general, during her nine years as a show runner. Speaking to Oprah about her greatest accomplishment over that time, she says: "I think I'm most proud of the fact that I have figured out how to exist as both a creative person and artist, and a businesswoman and manager. Because those two things do not go together."

"For a long time," she continues, "I really had a hard time with the idea that I was supposed to be this person who lived inside her head and created things but also managed a bunch of people and had to lead a group of people. And those two things have sort of come together. And I'm really proud of how that works now."